Photographic color former dispersions



July 30, 1957 s. s. FIERKE ETAL 2,301,171

PHOTOGRAFHIC CULQR FORMER DISPERSIONS Filed Dec. 20, 1954 LESS THAN [PART PER PART OF COUPLER a: H/G'fi- BOILING CRYSTZLLO/OAL SOLVEN T LOW-BOILING WAT ER- INSOLUBLE SOLVENT O aWATER-SOLUBLE SOLVENT, 0/? BOTH GEL A TIN SOLUTION s/u/m HAL/0E l EMULSION I I I 1 I SOHEUR/NG S. F/ERKE JONAS 11 OHECHAK IN VEN TORS ATTORNEYS United States Patent Ofiice 2,801,171 Patented July 30, 1957 PHOTOGRAI'HIC COLOR FORMER DISPERSIONS Scheuring S. Fierke and Jonas John Chechak, Rochester,

N. Y., assignors to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey Application December 20, 1954, Serial No. 476,561

Claims. (Cl. 96-97) This invention relates to color photography and particularly to a method for incorporating couplers in silver halide emulsion layers.

In preparing dispersions of color-forming compounds in silver halide emulsions it is customary to dissolve the color former or coupler in a suitable high boiling solvent, disperse this solution in aqueous gelatin and mix the resulting dispersion with the sensitive silver halide emulsion before coating. Ratios of coupler to solvent of about 1 to 2 or 1 to 3 are usually employed (see examples of Jelley and Vittum U. S. Patent 2,322,027), although with some couplers a ratio of l to 1 can be used successfully. The true solubility of the couplers in the coupler solvents is, however, considerably lower than is indicated by the above ratios and in many cases does not exceed one part of coupler in ten parts of coupler solvent. The dispersed phase in most color former dispersions incorporated in emulsion layers is, therefore, usually a highly supersaturated solution.

Even in the coupler-to-solvent ratios usually employed a large amount of inert solvent is introduced into the emulsion and this is disadvantageous because the inert material has no photographic function and because it tends to decrease the physical hardness of the emulsion layers.

In order to reduce to a minimum the amount of the inert ingredients in the emulsion layer and to improve the physical hardness of the coatings, it would be desirable to use smaller quantities of coupler solvent than those corresponding to the above ratios. To this end, efforts have been made to prepare coupler dispersions using smaller ratios of coupler solvent, representing, for example, ratios of coupler to solvent of 1 to $6 or 1 to Mt. Such low ratio dispersions have been successfully prepared in some cases using auxiliary solvents which are removed during the course of preparing the dispersion. The same technique has been applied to the preparation of coupler dispersion containing substantially no coupler solvent.

With some couplers, recrystallization occurs with these low ratio dispersions. Crystal-free dispersions containing no coupler solvent can be obtained but these dispersions nearly always yield less dye upon color development, unless the developing solution contains an organic solvent such as benzyl alcohol and hence, have only a limited usefulness where normal color processing is required.

We have found that low ratio coupler dispersions may be prepared by (I) dissolving the coupler in a solvent including a low boiling substantially water-insoluble organic solvent, or an appreciably water-soluble organic solvent, for the coupler, and less than about one part per part of coupler of a substantially water-insoluble low molecular weight organic crystalloidal solvent for the coupler, the crystalloidal solvent having a boiling point above about 175 C. and having a high solvent action for the coupler and for dyes formed therefrom and being permeable to photographic developer oxidation products, (2) dispersing the solution in gelatin, (3) chilling and setting the gelatin dispersion, (4) removing at least of the water and substantially all of the low boiling substantially water-insoluble organic solvent, or the appreciably water-soluble organic solvent, from the dispersion by drying or by washing with water and then drying, and (5 mixing the dried dispersion at any subsequent time with a gelatino-silver halide emulsion.

The accompanying drawing is a diagrammatic illustration of the steps in our process.

As shown in the drawing, a mixing tank 1 provided with a suitable stirring device 2 may be used to produce the solution of the coupler in the solvent or mixture of solvents. The low-boiling water-insoluble solvent or the water-soluble solvent or both is added through pipe 3 to dissolve the coupler, and the crystalloidal high-boiling solvent may also be added to the tank, if employed. After solution of the coupler in the solvent mixture, the solution is passed to a second tank 4 where gelatin solution is added, and the solution then homogenized in a colloid mill 5 and passed to the gel plate 6 where it is chilled and set by means of cooling coils 7.

The chilled dispersion is then noodled and either air dried directly as shown at 8 or first washed with water from a spray nozzle 9 as shown at 10 and then air dried as shown at 8. The water washing step is required only if the coupler dispersion was made using a water-soluble solvent or mixture of water-soluble and water-insoluble solvents. If only the low-boiling water-insoluble solvent was used, the water washing step is not required and the dispersion can be directly air dried as shown at 8.

In either case, the dry dispersion is then mixed with a silver halide emulsion in tank 10 to form the final gelatino-silver halide emulsion containing the coupler dispersion.

Couplers which may be used according to our invention are those disclosed in Ielley and Vittum U. S. Patent 2,322,027 and the following:

(1) 1-hydroxy-2-[5-(2,4'-di-tert.amylphenoxy) n bu tylJ-naphthamide (U. S. Patent 2,474,293)

(2) 1-hydroxy-4-phenylazo 4' (p-tert.butylphenoxy)- 2-naphthanilide (U. S. Patent 2,521,908)

(3) 2-(2,4-di-tert.amylphcnoxyacetamino)-4,6 dichloro- 5-methyl phenol (Graham U. S. Patent 2,725,291)

(4) 2 (a-Di-tert.amylphenoxy-n-butyrylamino) 4,6-

dichloro-S-methyl phenol (5) 6 {{a- {4-[01-(2,4-di-tert.amylphenoxy)butyramido] phenoxy}-acetamido}}-2,4-dichloro-3-methyl phenol (6) 2 l3'-(2",4"-diamylphenoxy)-acetamido] benzamido-4-chloro-5-methyl phenol (7) 1-(2',4',6'-trichlorophenyl)-3-[3" (2",4'-di-tert. amylphenoxy-acetamido)-benzamidoi S-pyrazolone (U. S. Patent 2,600,788)

(8) 1-(2',4',6', trichlorophenyl) 3 [3"-(2"',4"'-di-tertamylphenoxy-acetamido-benzamido1 4 (p-methoxyphenylazo -5 -pyrazol one (9) N-(4-benzoylacetaminobenzenesulfonyi) N phenylpropyl)-p-to1uidine (U. S. Patent 2,298,443)

(10) a-o-methoxybenzoyl-a-chloro 4 [a-(2,4-di-tert.-

amylphenoxy)-n-butyramido]-acetanilide (McCrossen U. S. Patent 2,728,658)

(11) (1!{3 [a (2,4-di-tert.amylphenoxy)acetamido1- benzoyl}2-methoxy-anilide (l2) 3-benzoylacetamino-4-methoxy 2',4-di-tert.amylphenoxyacetanilide (l3) 4-benzoylacetamido-3 methoxy-2,4'-di-tert.amylphenoxyacetanilide 3 Couplers Nos. 4, 5, 6, 8, ll, 12 and 13 were prepared as follows:

COUPLER No. 4

2- a-Diamylphenoxy-n-butyry lamino) -4,6dichlr0-5- methyl phenol In a 2 l. 3-necked flask equipped with a stirrer, reflux condenser and a thermometer was placed a solution of 600 cc. of acetone (dried over sodium sulfate) and 80 g. (0.62 mole) of redistilled quinoline (pract.). To this solution was added 685 g. (0.30 mole) of recrystallized 2 amino 4,6 dichloro-S-methyl phenol hydrochloride. The hydrochloride dissolved partly with a yellow color. Soon a white solid separated abundantly but the mixture remained readily stirrable. Stirring was continued for 10 minutes and then there was introduced 101 g. (0.3 mole) of a-diamylphenoxy-n-butyryl chloride. The temperature rose switfly from 28 to 46 C. Some solid remained out of solution.

The mixture was heated for 1 hours on the steam bath with continuous stirring. At no time was solution complete. The mixture was cooled externally to 10 C. and to it was added 1 l. of ice water. The mixture was made acid to Congo paper by the introduction of 15 cc. of concentrated hydrochloric acid. A few seeds of prod uct from a previous preparation were added and stirring continued for one hour. The product separated as a white cheese-like ball. The acidic aqueous liquor was decanted and replaced by 1200 cc. of petroleum ether in which the product dissolved readily. The petroleum ether solution was washed successively with 500 cc. of water containing 25 cc. of concentrated hydrochloric acid, 500 cc. of water, 500 cc. of 2% sodium bicarbonate solution, 500 cc. of water.

The product, which might crystallize during the Washing operations, was dissolved by the use of more petroleum ether.

The petroleum ether solution was dried over anhydrous calcium chloride and filtered by suction. Again, any product which separated might be dissolved by more solvent. The clear pink filtrate was concentrated on the steam bath to a volume of 600 cc. From this volume of solvent the product crystallized within an hour as fine white feathery needles. The mixture was cooled in an ice bath, stirred smooth, filtered by suction and the product washed on the funnel with 3 x 100 cc. of cold petroleum ether. Product was white, giving no trace of color in solvents. M. P. 117-118. Yield: 62 g.

The product was dissolved in 2 l. of petroleum ether by warming slightly. To the water-white solution was added 5 g. of Darco (activated carbon) and the mixture was filtered by suction through a layer of 5 g. of Darco on a Buchner funnel. The colorless filtrate was concentrated to a volume of 200 cc. and the product crystallized. The mixture was stirred smooth, cooled externally to 0 C. and filtered. The produce was washed on the funnel with 100 cc. of cold petroleum ether (0 C.). The solid was dried at 50 C. Yield: 53 g. (37%), M. P. 123124 C.

2-amin0-4,6-dichl0r0-5-methyl phenol hydrochloride In a l l. beaker was placed 100 g. (0.634 mole) of 2-amino-4-chloro-S-methylphenol (J. fiir Prakt. Chem. 91, 414) and 450 cc. of glacial acetic acid, and the mixture was stirred as smooth as possible with a glass rod; the temperature rose from 23 to 35. To this slurry was added all at once 132 cc. (142 g., 1.4 moles) of acetic anhydride, the temperature now rising to 55". At no time was a solution formed because the acetyl derivative crystallized almost immediately. This mixture was stirred smooth with a rod and left standing for 1% hour. The slurry was then cooled to 20 and 55 cc. (92 g., 0.68 mole) of practical sulfuryl chloride added all at once. The temperature rose to 46, a red solution being formed. As soon as solution was complete and before the new chloro compound could crystallize, the liquid was transferred to a 3 l. 3-necked flask provided with a stirrer and reflux condenser. After 10 minutes to the now crystal-containing mixture was added a solution of 500 cc. of denatured ethyl alcohol and 500 cc. concentrated hydrochloric acid.

The mixture was boiled while stirring. After 5 minutes at the boil, crystals of hydrochloride began to separate. The mixture was refluxed for 45 minutes after the first appearance of solid. The mixture showed appreciable tendency to foam, especially if boiling was rapid. The mixture was cooled overnight and filtered by suction (brown filtrate). The solid on the filter was washed with l6 1. of acetone, a white hydrochloride being thus obtained. Dried at 70. Yield: 113 g. (78%).

A sample of free amine liberated by sodium bicarbonate from this hydrochloride melted at 133134.

a-Diamylphenoxy-n-butyric acid In a 3-liter three-necked flask, equipped with a stirrer, thermometer and reflux condenser was placed 40 cc. of water and 660 cc. of denatured alcohol. In the alcohol was dissolved 80 g. (2.0 mole) of caustic soda pellets by stirring and heating at a boil. Stirring was maintained throughout the preparation. To this hot solution was added 234 g. (1.0 mole) of redistilled di-tert-amyl phenol and refluxing was continued for 5 minutes. The solution was cooled externally to 60 C. and 167 g. (1.0 mole) of a-bromo-n-butyric acid was added. The temperature of the solution rose 15 C. The solution was heated to a boil and boiling under the reflux was maintained for 3 hours. Some separation of salt occurred.

The mixture was cooled externally to room temperature and diluted with 1 liter of ice water and 200 cc. of concentrated hydrochloric acid. The resulting mixture showed a strong acidity on Congo paper. The oily product was extracted with 500 cc. of ethyl ether (tech.) and the ether extract was washed with 500 cc. of water. The ether solution was separated and transferred to a suitable Claisen flask. The moist ether extract was concentrated by distillation, final traces of ether and water being removed by suction.

The syrupy residue was distilled in vacuo, an oil bath being used until all traces of diamyl phenol had been recovered. In the distillation a fore-run of about 15 g. was collected up to /1 mm. The diamyl phenol was collected at 11l-l69/1 mm., g. of it being recovered. Nearly all of the diamyl phenol boils at 123-l25/l mm. The oil bath was removed and the a-diamylphenoxy-n-butyric acid was distilled over a flame. The product was collected at l70-200/l mm. This product can be recognized by the sudden increase in the viscosity of the distillate. No appreciable residue was left in the still. Yield: 125 g. (39%).

a-Diamylphenoxy-n-butyry! chloride In a 500 cc. Claisen fiask was placed 160 g. (0.5 mole) of a-diamyl phenoXy-n-butyric acid and 160 g. (1.35 mole) of thionyl chloride (distilled over quinoline). On being warmed to 40 C. a gentle evolution of sulfur dioxide and hydrogen chloride commenced in the clear amber liquid. The temperature was held at 40-45" C. until the evolution of gas had ceased. This generally occurred after three hours.

Excess thionyl chloride was removed by distillation. final traces of it being distilled by vacuum at the water pump. The a-diamylphenoxy-n-butyric chloride was distilled at l38l40/l mm. Yield g. (90%).

COUPLER NO. 5

6{{a {4-[a (2,4-diterf-amylphenoxy)hutvramidol phenoxy}acetamida}}-2,4-dich[era-3-methylpherzo! In a 500 ml. 3-necked flask were mixed 14.8 g. (.045 mole) of 6- [a-(4-aminophenoxy) acetamido]-2,4-dichlcro- S-rnethylphenol, 250 ml. of acetone, 5.5 mi. (.0455 mole) of dimethylaniline, and 15 g. (.0445 mole) of u-(2,4-ditert-amylphenoxy)-n-butyryl chloride (see above) with mechanical stirring. The flask was equipped with a watercooled condenser and the reaction mixture was refluxed for 2 hours. The cooled reaction mixture was poured into 1 liter of cold water containing 2 ml. of concentrated hydrochloric acid with stirring, and the solid that was formed was filtered, washed well with cold water, and dried. The product, 31.5 g. crude, was crystallized twice from methyl alcohol using Darco once. There was obtained 19.8 g. of white material melting at 1202 C. which is 50% of the 37.8 g. theoretical amount.

6- [a- (4 nitrophenoxy acetamido -2,4-dichlr -3-methylphenol 2-amino-4,6-dichloro-S-rnethyl phenol hydrochloride, 107 g. (.48 mole), was mixed in a 2-liter flask with 900 ml. of acetone and 121 ml. (1 mole) of dimethylaniline and while stirring vigorously 107.5 g. (.5 mole) of p-nitrophenoxyacetyl chloride was added to the flask in about 5 minutes. The flask was equipped with a reflux condenser and the mixture was refluxed for 2 hours. At the end of this time the reaction mixture was added to 2.5 l. of cold H2O containing 8 cc. of concentrated HCl. An oil formed and it was washed by decantation several times with cold water. Denatured alcohol was added to the oil, and soon a crystalline precipitate formed. It was filtered,

washed with fresh denatured alcohol and dried in a hot' oven. Yield was 153 g., 86%, M. P. 2402. A sample was crystallized from dimethylformarnide with a recovery of 62%, M. P. 241-2 C.

6-[01 (4 aminophenoxy)acetamidol 2,4 dichl0r0-3- methylphenol The nitro compound 37.1 g. (.1 mole) was placed in a pressure bottle with about 3 g. of nickel catalyst and 200 ml. of pyridine. The bottle was placed on the Parr hydrogenator and shaken at 4050 under 38 pounds of hydrogen pressure. The required .3 mole of hydrogen was taken up rapidly, and after 2 hours the catalyst was filtered out of the water-white pyridine solution and the solvent removed under reduced pressure from a water bath at 50. The white, solid residue was broken up and triturated with 200 ml. of methyl alcohol, filtered and dried. Yield was 30 g. which is 93% of the 32.7 g. theoretical amount, M. P. 256-8. A sample crystallized from dimethylformamide melted at 26 l3 C.

p-Nitrophenoxyacetic acid In a 5-liter flask were placed 278 g. (2 moles) of pnitrophenol, 190 g. (2 moles) of chloroacetic acid, 168 g. (4.2 moles) of sodium hydroxide and 2 liters of water. The mixture was boiled in the open flask until it showed a neutral reaction to litmus paper. The reaction temperature reached 115 C. and some water was evaporated. When the neutral point had been reached (2.5-3 hours) an additional 84 g. (2.05 moles) of sodium hydroxide and 95 g. (1 mole) of chloroacetic acid were added to the flask and the heating continued until a neutral reaction again resulted.

To the cooled reaction mixture was added 500 ml. of concentrated hydrochloric acid with stirring. The solid formed was filtered, slurricd with 3 liters of ice cold water and again filtered and washed with 1 liter of ice cold water. The dry product melted at l82-l84 C. and weighed 300 g. Yield was 76% of the 394 g. theory. It may be crystallized from denatured alcohol, if desired.

p-Nitrophenoxyacetyl chloride In a 500-ml. flask were mixed 19.7 g. (0.1 mole) of p-nitrophenoxyacetic acid and 100 ml. of thionyl chloride. The mixture was refluxed for 5 hours on a steam bath and the excess thionyl chloride removed under reduced pressure. The removal of the thionyl chloride was continued until the residue had reached constant weight. The acid chloride was used without purification and gave good results. It may be crystallized from dried ligroin to obtain a white crystalline material melting at 86-87 C.

COUPLER NO. 6

4 -ch l0r0-2-{3-[a- (2,4-di -tert-amyl phenoxy acetamido} benzam ido}-5-methylphen0l added, at 25, with stirring over a period of 4 minutes, a

solution of 34.1 g. (0.11 mole) of e-(2,4-di-tert-amylphenoxy)acety1 chloride in cc. of dry acetone. The temperature rose rapidly to 38 and a complete solution resulted. The clear solution was stirred in an ice-water bath for one hour (the resultant temperature being approximately 5), and cc. of 10% hydrochloric acid was added. The temperature rose to 15, and the white slurry was stirred for one hour, filtered, and dried at approximately 50 to constant weight. The yield of coupler was 46 g. (83%). The melting point was -66 C.

2- (S-nitrobenzamido) -4-chlor0-5 -methy1phenol In a 2-liter Erlenmeyer flask were placed 158 g. (1.0 mole) of 2-amino-4-chloro-5-methylphenol (Journal fiir praktische Chemie 91, 414 (1915)) and 1.2 liters of dry acetone. To this solution was added 20 g. of Darco, and the resultant mixture was left to stand for approximately 5 minutes at room temperature, then filtered by suction.

In a 5-liter, B-necked, round-bottom flask equipped with a thermometer and stirrer was placed the above solution, and to it was added 121 g. (1.0 mole) of N,N-dimethylaniline (97%). This solution was cooled to 10 in an ice-water bath, and a solution of 186 g. (1.0 mole) of mnitrobenzoyl chloride in 540 cc. of dry acetone was added with stirring over a period of 4 minutes. The temperature rose rapidly to 38 and the product separated in the form of a fine white solid. This mixture was stirred in the ice-water bath for a total of 2 hours. The product was filtered oil by suction, washed on the funnel with 3 x 300 cc. of acetone and dried in the steam chest to constant weight. The yield was 285 g. (93%), and the melting point was 273-274" C.

2-(3-aminobenzamido)-4-chloro-5-methylphenol In a 2-liter, B-necked, round-bottom flask equipped with a condenser and stirrer was suspended 61 g. (0.2 mole) of 4-chloro-5methyl-2-(3-nitrobenzamido)phenol in 600 cc. of 90% acetic acid. To this suspension, which was heated first to reflux, was added 62 g. of iron powder.

The mixture was refluxed with stirring for a total of onehalf hour, during which time the nitro compound dissolved and the froth over the refluxing solution became colorless. The solution was filtered and the filtrate was drowned in 2 liters of water. The amine which separated as a fine white solid was filtered and washed on the funnel with 2 x 250 cc. of 10% acetic acid and 8 x 250 cc. of water and dried at approximately 50 to constant weight. The yield of product was 50 g. (93%). The melting point was 205-6 (recrystallized amine melts at 216-18).

2,4-di-tert.-amylphenoxy acetic acid then cooled to 60 and 94.5 g. (1.0 mole) of chloroacetic acid added. The mixture was refluxed with stirring for three hours, cooled to room temperature, diluted with 1 liter of ice water and acidified with 200 cc. of cone. hydrochloric acid. The diamylphenoxy acetic acid, separated as an orange-brown oil, was extracted with 200 cc. of ether and the wet ether layer concentrated under reduced pressure on the steam-bath. The heavy oil was vacuum distilled, collecting at 172-l76 at 1 mm./Hg. Yield: 127 g. (43%). The viscous oil soon solidified to a wax-like solid. The diamylphenoxy acetic acid can be purified by recrystalliaztion from hexane, M. P. l l6-117; snow-white powder.

o=-(2,4-di-tert.-amylphenxy acetyl chloride Eighty grams (0.27 mole) of 2,4-diamylphenoxy acetic acid was melted on the steam-bath and cooled to 50. To the semi-solid was added 88 g. (0.74 mole) of thionyl chloride (redistilled over quinoline) and the mixture stirred until all of the solid dissolved. The clear liquid was placed in a 500 cc. flask equipped with stirrer and thermometer and heated with stirring at 40-45 for 4 hours. Excess thionyl chloride was removed by warming under reduced pressure at a water pump. The product was collected at 143146/2 mm. Yield: 65 g. (76.5%).

COUPLER NO. 8

1 (2,4',6' trichlorophenyl) 3-[3"-(2',4"'-diamylphenoxyacetamido) -benzamid0 -4-(p-meth0xyphenylaz0) S-pyrazolone 1 (2',4',6-trichlorophenyl)-3-[3"-(2",4'-diamylphenoxyacetamido)-benzamido]-5-pyrazolone (92 g.) was dissolved in 1.25 liters of pyridine and the solution cooled to 0 C. In the meantime the diazonium solution was prepared by dissolving 19.4 g. of p-anisidine in 250 cc. of water plus 40 cc. of concentrated hydrochloric acid, cooling to 0 C. and adding 11.2 g. of sodium nitrite in 100 ml. of water. The diazotization was run at a temperature not exceeding 5. The diazonium solution was diluted with 500 cc. of denatured alcohol, treated with decolorizing carbon, and filtered.

This clarified solution was now added to the pyridinecoupler solution at such a rate that the temperature did not exceed Stirring was continued for 0.5 hour after the addition was complete and the temperature was al lowed to rise to 25. The reaction mixture was diluted with twice its volume of water, whereupon the dye precipitated as a gum. The liquor was decanted from the gum which was washed well with Water. The gum was dissolved in two liters of boiling denatured alcohol. The cooled solution yielded an orange powder which was recrystallized from about 80 parts of denatured alcohol. The yield was 70 g. (63%) of dye which exhibited strange melting characteristics. Different samples have melted at 133-135", 149452", 147-150", and 142-144 after sintering at 138.

COUPLER NO. 11

a-3-[ot-(2,4-tert-mflylphcnary acetnmid01-hcuzoy Z- meth oxyacctmzilide In a 500 cc. three-necked flask, provided with a stirrer and thermometer, were placed 300 cc. of 90 percent acetic acid and 30 g. (0.36 mole) of anhydrous sodium acetate. To this solution, at room temperature, was added 32.0 g. (0.1 mole) of a-(m-aminobenzoyl)-2-methoxy-acetanilide hydrochloride, an easily stirrable mixture resulting as the temperature dropped 2. After this mixture had been stirred for one-half hour, 37 g. (0.19 mole) of 2.4-di-tertamylphenoxyacetyl chloride (see above) was added during approximately one-half minute. The reaction mixture became much thinner, but failed to clear up as the temperature rose from 25.5 to 33.5"; color was a pink-gray. Following one and one-half hours of stirring, the mixture was diluted dropwise over a period of one-half hour with 30 cc. of water and seeded with coupler. Further stirring overnight caused separation of product as a finely divided white mass.

" trope.

The reaction mixture was drowned with stirring during fifteen minutes in 600 cc. of water, the product separating in white granules. Stirring was continued for fortyfive minutes and the mixture filtered readily through a 5-inch Buchner funnel. The White solid was washed on the funnel with 2 liters of water, not over 20". Immediately, when the cake was no longer covered by water, it shrank in a characteristic manner away from the edge of the funnel as though threatening to become gummy. This change failed to occur as the cake was sucked and pressed thoroughly. The solid, which could be broken up easily, was air-dried, 60 g. being obtained; it had an indistinct melting range, starting at about Twelve hundred cc. of cyclohexane was heated to a boil on the steam bath and the 60 g. of crude product dis solved therein, forming a pink solution. It was treated with 2 g. of Darco and the solution filtered hot through 2 g. of Darco on a 4-inch Buchner funnel. Clear filtrate was only slightly less colored than prior to the Darco treatment. The coupler was permitted to crystallize un disturbed overnight. It was filtered readily, washed on the funnel with three -cc. portions of fresh cyclohexane. The yield was 47 g. (82 percent of the theoretical amount) of white coupler, which melted at 126 127.

a-(m-Nitrobenzoyl) -2-methoxyacetam'lide To a refluxing mixture of 22 g. (.093 mole) of ethyl a-(m-nitrobenzoyl)acetate (B'tilow & Hailer, Ber. 35, 915 (1902)) in ml. of histological xylene was added in one portion 11 g. (.09 mole) of o-anisidine. The mixture was heated at the reflux temperature (oil bath at l4555) for two hours under a steam-jacketed stillhead, which permitted the removal of the alcohol-xylene azeo- The product which separated from the cooled reaction mixture was filtered and sucked dry on a Buchner funnel; the yield of yellow product was 24 g. (82%), M. P. 166-7.

a (m Aminobenzoyl) 2 mctlzoxyacetanilide hydrochloride In a l2-liter one-necked flask (utilizing a three-holed rubber stopper) equipped with a stirrer, thermometer and reflux condenser was suspended 150 g. of a-(rn-nitrobcnzoyl)-2-methoxyacetanilide in a solution of 2.5 1. of acetone and 500 cc. of concentrated hydrochloric acid. To this mixture was added with stirring 150 g. of plast iron over a twenty-minute period. The reaction was very exothermic; as it proceeded more and more of the nitro compound went into solution and the color of the solution became a dark yellow-brown. The heat of re action resulted in the boiling point of acetone being attained and after addition of the entire amount of iron. the solution was stirred for a ten-minute period. At this point 100 cc. of water was introduced in the reaction mixture and the solution was stirred an additional ten minutes. The temperature of the mixture had dropped to 50 C. and was then filtered. The cake was washed with 500 cc. of acetone and this brown combined filtrate and wash poured into 5 l. of dilute hydrochloric acid (4.5 l. of water and 500 cc. of concentrated hydrochloric acid). The solution was allowed to stand for twentyfour hours. It was then filtered and the cake washed with two 500 cc. portions of water containing a trace of hydrochloric acid. The solid was removed and slurried with 500 cc. of acetone, filtered and dried. The yield of white crystalline hydrochloride was 104.5 g. (68% of the theoretical amount).

COUPLER NO. 12

(0.02 mole) of m-benzoyl-S-amino-2-methoxyacetanilide, 2 grams (0.02+ mole) of anhydrous sodium acetate, and

100 ml. of glacial acetic acid. With good stirring 6.2 grams (0.02 mole) of 2,4-di-tert-amylphenoxyacetyl chloride (see above) in 25 ml. of glacial acetic acid was added all at once. The reaction mixture was stirred 1 hour at room temperature and '6 hour at 60. After cooling to room temperature, the reaction mixture was poured with vigorous stirring into 1 liter of cold water. The moist solidwas filtered, washed with cold water, sucked as dry as possible, and recrystallized from 200 ml. of denatured alcohol. The yield was 7.5 grams (67 percent) of a tan powder which melted at 124l26. Recrystallization from 200 ml. of alcohol gave 6.2 grams (55 percent) of a product which melted at 132-l34.

u-Benzoyl-Z-methoxy-S-nitroacetanilide In a 250-ml. round bottom flask equipped with a partial condensing still-head were placed 100 ml. of histological xylene and 16.8 grams (0.1 mole) of 4-nitro-2-aminoanisole (Ber. 13, 389). The mixture was brought to a. boil and 19.2 grams (0.1 mole) of ethyl benzoylacetate was added all at once. After refluxing 2 hours, about 3-5 ml. of ethyl alcohol had been collected. The yellow solution was filtered hot and allowed to cool to room temperature. The yellow solid which separated was filtered, washed with 50 ml. of xylene, and finally with 100 m1. of petroleum ether. A crude yield of 26 grams (83 percent) was obtained which melted at 170-175 C. On recrystallization from 18 parts of glacial acetic acid, 22.4 grams (71 percent) of fine light yellow needles, M. P. 177179, was obtained.

a-Benzoyl-S-tlmino-Z-methxyacetanilide In a Parr hydrogenation bottle were placed 16 grams (0.051 mole) of a-benzoyl-2-rnethoxy-5-nitroaeetanilide, 250 m1. of absolute ethyl alcohol, and 2-5 grams of Raney nickel. The reaction mixture was shaken under 2-3 atmospheres of hydrogen overnight at room temperature. The nickel was removed by filtration and the filtrate cooled in an ice bath. The light yellow solid was filtered, washed with 50 ml. of cold methyl alcohol, and dried. The yield was 13 grams (90 percent) of a solid which melted at 108-110 C.

COUPLER NO. 13

4-benzoylacetamido-3-methoxy- (2',4'-di-tert-amylphenoxy)aceraniiide In a SOD-ml. Erlenmeyer flask equipped with a stirrer were placed 16 g. (0.05 mole) of a-benzoyl-4amino-2- methoxyacetanilide hydrochloride and 10 g. (0.1+ mole) of anhydrous sodium acetate in 200 ml. of glacial acetate acid. With good stirring 16 g. (0.051 mole) of 2,4-ditert-amylphenoxyacetyl chloride (see above) were added. After stirring at room temperature for one hour, the reaction mixture was heated to 60 for one-half hour, cooled, and poured with very vigorous stirring into two liters of cold water. After stirring until the precipitate was filterable, the solid was filtered, washed with 500 ml. of water, and sucked as dry as possible. The moist solid was recrystallized from 5-10 parts of denatured alcohol to give 16.3 g. (58.4%) of white material which melted at 163-165.

a-BenzoyI-Z-methoxy-4-nitroacetanilide In a 250-ml. round-bottom flask equipped with a partial condensing s-tillhead were placed 33.6 g. (0.2 mole) of 2-methoxy-4-nitroaniline (Ber. 13, 390) and 75 ml. of histological xylene. The mixture was refluxed for five minutes before 40 ml. (0.22 mole) of ethyl benzoyl acetate was added. About 9 ml. of distillate was collected in two hours. The brown solution was filtered from mechanical impurities and allowed to stand at room temperature overnight. The precipitate was filtered, washed with 100 ml. of xylene, washed with 100 ml. of petroleum ether, slurried with 200 ml. of denatured alco- 1 he], and dried. The yield was 39 g. (62%) of a yellow solid which melted at 179-l80 C.

a-Benzoyl-hamino-Z-methoxyacetanilide hydrochloride In a one-liter 3-necked flask equipped with a reflux condenser were placed 31.4 g. (0.1 mole) of a-benzoyl-2- methoxy-4-nitroacetanilide, 200 ml. of 50% aqueous denatured alcohol, and ml. of glacial acetic acid. The mixture was brought to a boil, the heat was removed, and 31.4 g. of iron powder was added as rapidly as possible. When the initial reaction had subsided, heat was again applied and the reaction mixture was refluxed 20 minutes. After filtration the filtrate was diluted as rapidly as possible with one liter of water and 300 ml. of concentrated hydrochloric acid. The solution changed from a deep brown to a deep yellow. After chilling overnight at 5 C., the hydrochloride was filtered, washed well with 500 ml. of 5% hydrochloric acid and 500 ml. of cold water. After drying 24.8 g. (77%) of an off-white solid was obtained which turned red in patches ca 150, losing HCl ca 200", and melted with decomposition at 206-209".

High boiling organic crystalloidal coupler solvents which may be used according to our invention include (1) alkyl esters of phthalic acid in which the alkyl radical preferably contains less than 6 carbon atoms, e. g., methyl phthalate, ethyl phthalate, propyl phthalate, n-butyl phthalate, di-n-butyl phthalate, n-arnyl phthalate, isoamyl phthalate and dioctyl phthalate, (2) esters of phosphoric acid, e. g., triphenyl phosphate, tricresyl phosphate and diphenyl mono-p-tert. butyl phenyl phosphate, and (3) alkyl amides or acetanilide, e. g., N,n-butylacetanilide and N-methyl-p-methyl acetanilide.

Low boiling water-insoluble organic solvents in which the coupler is first dissolved and which are removed to form the substantially dry dispersion of coupler in gelatin include methyl, ethyl, propyl and butyl acetates, isopropyl acetate, ethyl propionate, sec. butyl alcohol, carbon tetrachloride and chloroform, which are volatile solvents and can be removed by air drying. Water-soluble organic solvents include methyl isobutyl ketone, ,B-ethoxy ethyl acetate, fi-butoxy fi-ethoxy ethyl acetate, tetrahydrofurfuryl adipate, Carbitol acetate (diethylene glycol monoacetate), methoxy triglycol acetate, methyl Cellosolve acetate, acetonyl acetone, diacetone alcohol, butyl Carbitol, butyl Cellosolve, methyl Carbitol, methyl Cellosolve, ethylene glycol diethylene glycol and dipropylene glycol. Certain of these water-soluble solvents, e. g., Carbitol acetate, butyl Cellosolve, have high flash points, and therefore reduce the fire hazard during removal from the emulsion. The water-soluble solvents are removed from the emulsion by washing with water.

The coupler is dissolved in a solvent or solvent mixture of such composition that the ratio of coupler to high boiling organic solvent will be one part of coupler to less than one part of high boiling solvent. The solvent will always contain low boiling organic solvent, which is removed during preparation of the emulsion coating, and may contain high boiling organic solvent in the proper ratio, or may be entirely free of high boiling solvent, in which case a solventfree" coupler dispersion is obtained in the final coating. It is usually desirable, however, to have some high boiling organic solvent in the final coating.

A suitable ratio of coupler to high boiling organic solvent, as shown by the following examples, would be 8 grams of coupler to 4 cc. of high boiling solvent, or a ratio of 19/2. The solvent mixture preferably contains ethyl acetate as the low boiling solvent and di-n-butyl phthalate as the high boiling solvent, although other mixtures and ratios varying within the scope expressed above may obviously be employed.

Our invention will now be illustrated by the following examples:

EXAMPLE 1 Eight grams of the coupler l-(2,4',6'-trichlorophenyl)- di tert. amylphenoxyacetamido)- benzarnido1-5-pyrazolone were dissolved in a solution of 25 cc. of ethyl acetate and 4 cc. of di-n-butyl phthalate at the reflux temperature of ethyl acetate. This mixture was then poured into a solution of 65 cc. of 10% gelatin solution and 8 cc. of Alkanol B (sodium triisopropylnaphthalene sulfonate) solution at 50 C., stirred for about 1 minute and run through a colloid mill five times, after which the mill was rinsed with 25 cc. of water. The dispersion was set up on a chill plate at 40 F., noodled and air dried at 78 C. and 50% relative humidity. Total dry weight of the dispersion was 18.5 grams and it falls persed in gelatin into particles of less than 0.5 mg with no apparent crystals.

EXAMPLE 2 100 grams of the coupler used in Example 1 was dissolved in 250 cc. of ethyl acetate at a reflux temperature of ethyl acetate. This solution was poured into a solution containing 800 cc. of gelatin solution and 100 cc. of 5% Alkanol B solution and then milled 5 times in a colloid mill. 50 cc. of water was used to rinse the mill. The dispersion was set up on a chilled plate at 40 F., noodled and air dried at 78 C. and 50% relative humidity. Total weight of the dispersion was 193 grams.

7.9 grams of this dispersion was added to a gelatinosilver halide emulsion containing approximately 0.046 mole of silver halide. After coating on a film support the emulsion was exposed and processed in a developer of the following composition and was found to produce a satisfactory magenta dye density:

Grams p-Amino diethylaniline sulfate 2 Sodium sulfite, anhydrous 5 Sodium carbonate, anhydrous 20 Potassium bromide 2 Benzyl alcohol 10 Water to 1 liter.

Other primary aromatic amino developing agents may be used in place of the p-amino diethylaniline.

EXAMPLE 3 Eight grams of the coupler used in Examples 1 and 2 grams of dioctyl hydroquinone were dissolved in 25 cc. of ethyl acetate at the reflux temperature of ethyl acetate. This solution was poured into a solution containing 136 cc. of 10% gelatin solution and 16 cc. of 5% Alkanol B solution and was then milled 5 times in a colloid mill. Fifty cc. of water was used to rinse the mill.

8.4 grams of this dispersion were added to 133 grams of a gelatino-silver halide emulsion containing approximately 0.03 mole of silver halide. After coating on a film support, exposure and processing as in Example 2, the emulsion was found to produce a satisfactory magenta dye density.

EXAMPLE 4 Eighty grams of coupler No. 5 was dissolved in 40 cc. of dibutyl phthalate and 175 cc. of butyl Cellosolve. This mixture was poured into 545 cc. of 10% gelatin solution containing 35 g. of dissolved sodium sulfate and 70 cc. of a 7.5% solution of Alkanol B. This solution was passed through a colloid mill, chilled immediately, noodled and Washed with water. The coupler solvent (butyl Cellosolve) dissolves the coupler readily at low tcmperature, thus minimizing coupler decomposition, and is itself quickly washed from the emulsion after dispersion of the coupler. The dispersed particles prepared in this way are about .1 to .2 micron in diameter.

instead of couplers, antistain agents such as 2,5-diisooctyl hydroquinone and 2,5-di-n-octyl hydroquinone, and ultra-violet light absorbers such as 5-o-sulfobenzal-3- pheuyl-Z-phcnylimino-4-thiazolidone, may be dispersed in gelatin by our method.

It will be understood that our invention is to be taken as limited only by the scope of the appended claims.

We claim:

1. The method of incorporating a color former in a gelatino-silver halide emulsion which comprises dissolving a color-forming compound capable of reacting with a primary aromatic amino developing agent on photographic dcvelopment, in a solvent including at least a solvent selected from the class consisting of water-soluble organic solvents for the color-forming compound having a solubility of at least 2 parts of solvent in 100 parts of water and a boiling point above about 125 C., and low-boiling water-insoluble organic solvents for the color-forming compound having a boiling point below about 125 C. and a solubility of from .08 to 33 parts of solvent in 100 parts of water, and less than about one part per part of color-forming compound of a substantially water-insoluble, low molecular weight, organic crystalloidal solvent for the color-forming compound, said crystalloidal solvent having a boiling point above about 175 C. and having a high solvent action for the color-forming compound and for dyes formed therefrom, and being permeable to photographic developer oxidation products, dispersing the solution in aqueous gelatin, chilling and setting the gelatin dispersion, removing at least of the water and substantially all of said firstmentioned organic solvent from the dispersion to form a dry dispersion and mixing the dry color-former dispersion with a gelatino-silver halide emulsion.

2. The method of incorporating a color former in a gelatino-silver halide emulsion which comprises dissolving a color-forming compound capable of reacting with a primary aromatic amino developing agent on photographic development, in a solvent including at least a low-boiling water-insoluble organic solvent for the colorforming compound having a boiling point below about 125 C. and a solubility of from .08 to 33 parts of solvent in parts of water, and less than about one part per part of color-forming compound of a substantially water-insoluble, low molecular weight, organic crystalloidal solvent for the color-forming compound, said crystalloidal solvent having a boiling point above about 175 C. and having a high solvent action for the colorforming compound and for dyes formed therefrom, and being permeable to photographic developer oxidation products, dispersing the solution in aqueous gelatin, chilling and setting the gelatin dispersion, removing at least 90% of the water and substantially all of said lowboiling, water-insoluble organic solvent from the dispersion to form a dry dispersion and mixing the dry color-former dispersion with a gelatino-silver halide emulsion.

3. The method of incorporating a color former in a gelatino-silver halide emulsion which comprises dissolving a color-forming compound capable of reacting with a primary aromatic amino developing agent on photographic development, in a solvent including a water-soluble organic solvent for the color-forming compound having a solubility of at least 2 parts of solvent in 100 parts of water and a boiling point above about C., and less than about one part per part of color-forming compound of a substantially water-insoluble, low molecular weight, organic crystalloidal solvent for the color-forming compound, said crystalloidal solvent having a boiling point above about C. and having a high solvent action for the color-forming compound and for dyes formed therefrom, and being permeable to photographic developer oxidation products, dispersing the solution in aqueous gelatin, chilling and setting the gelatin dispersion, removing at least 90% of the water and substantially all of said water-soluble organic solvent from the dispersion to form a dry dispersion and mixing the dry color-former dispersion with a gelatino-silver halide emulsion.

4. The method of incorporating a color former in a gelatino-silver halide emulsion which comprises dissolving a color-forming compound capable of reacting with a primary aromatic amino developing agent on photographic development, in a solvent including at least ethyl acetate and less than about one part per part of colorforming compound of an alkyl ester of phthalic acid in which the alkyl group contains less than 6 carbon atoms, dispersing the solution in aqueous gelatin, chilling and setting the gelatin dispersion, removing at least 90% of the water and substantially all of said ethyl acetate from the dispersion to form a dry dispersion and mixing the dry color-former dispersion with a gelatino-silver halide emulsion.

5. The method of incorporating a color former in a gelatino-silver halide emulsion which comprises dissolving a color-forming compound capable of reacting with a primary aromatic amino developing agent on photographic development, in a solvent including at least ethyl acetate and less than about one part per part of colorforming compound of di-n-butyl phthalate, dispersing the solution in aqueous gelatin, chilling and setting the gelatin dispersion, removing at least 90% of the water and substantially all of said ethyl acetate from the dispersion to form a dry dispersion and mixing the dry color-former dispersion with a gelatino-silver halide emulsion.

6. The method of incorporating a color former in a. gelatino-silver halide emulsion which comprises dissolving a color-forming compound capable of reacting with a primary aromatic amino developing agent on photographic development, in a solvent including at least ethyl acetate and less than about one part per part of colorforming compound of di-n-butyl phthalate, dispersing the solution in aqueous gelatin, chilling and setting the gelatin dispersion, removing at least 90% of the water and substantially all of said ethyl acetate from the dispersion by air drying to form a dry dispersion and mixing the dry color-former dispersion with a gelatinosilver halide emulsion.

7. The method of incorporating a color former in a gelatino-silver halide emulsion which comprises dissolving a color-forming compound capable of reacting with a primary aromatic amino developing agent on photographic development, in a solvent including about three parts of ethyl acetate and about one-half part ppr part of color-forming compound of di-n-butyl phthalate, dispersing the solution in aqueous gelatin, chilling and setting the gelatin dispersion, removing at least of the water and substantially all of said ethyl acetate from the dispersion by air drying to form a dry dispersion and mixing the dry color-former dispersion with a gelatinosilver halide emulsion.

8. The method of incorporating a color former in a gelatino-silver halide emulsion which comprises dissolving a color-forming compound capable of reacting with a primary aromatic amino developing agent on photographic development, in about three parts of ethyl acetate per part of color-forming compound, dispersing the solution in aqueous gelatin, chilling and setting the gelatin dispersion, removing at least 90% of the water and substantially all of said ethyl acetate from the dispersion by air drying to form a dry dispersion and mixing the dry color-former dispersion with a gelatino-silver halide emulsion.

9. The method of claim 3, in which the water-soluble organic solvent is removed from the emulsion by washing with water.

10. The method of claim 3, in which the water-soluble organic solvent is butyl Cellosolve and the organic crystalloidal solvent is dibutyl phthalate, and the watersoluble organic solvent is removed from the emulsion by washing with water.

References Cited in the file of this patent UNITED STATES PATENTS 2,322,027 Jelley et al June 15, 1943 2,478,400 Jelley et at. Aug. 9, 1949 2,698,794 Godowsky Jan. 4, 1955 

1. THE METHOD OF INCORPORATING A COLOR FORMER IN A GELATINO-SILVER HALIDE EMULSION WHICH COMPRISES DISSOLVING A COLOR-FORMING COMPOUND CAPABLE OF REACTING WITH A PRIMARY AROMATIC AMINO DEVELOPING AGENT ON PHOTOGRAPHIC DEVELOPMENT, IN A SOLVENT INCLUDING AT LEAST A SOLVENT SELECTED FROM THE CLASS CONSISTING OF WATER-SOLUBLE ORGANIC SOLVENTS FOR THE COLOR-FORMING COMPOUND HAVING A SOLUBILITY OF AT LEAST 2 PARTS OF SOLVENT IN 100 PARTS OF WATER AND A BOILING POINT ABOVE 125* C., AND LOW-BOILING WATER-INSOLUBLE ORGANIC SOLVENTS FOR THE COLOR-FORMING COMPOUND HAVING A BOILING POINT BELOW ABOUT 125* C. AND A SOLUBILITY OF FROM .80 TO 33 PARTS OF SOLVENT IN 100 PARTS OF WATER, AND LESS THAN ABOUT ONE PART PER PART OF COLOR-FORMING COMPOUND OF A SUBSTANTIALLY WATER-INSOLUBLE, LOW MOLECULAR WEIGHT, ORGANIC 